Electrolytic Treatment of Laundry - Waste Produces Quality Effluent

Depending on power supply and treatment retention time, the electrolytic treatment can produce an effluent with a quality equivalent to or better than the control treatment of alum. A recent study of electrolytic treatment of laundry waste for water reuse has shown that because of the high concentration of total solids, the reuse of this effluent might be objectionable due to the extra consumption of soap or detergents. However, there is also a substantial saving of capital and operating cost with the electrolytic treatment, since no chemical storage space is required and operation is simplified. The proposed electrolytic system is applicable only to coastal areas and to inland areas where brine water is available; otherwise, the cost of salt becomes too expensive, mainly due to shipping charges. Treatment plants in many remote areas favor on-site generation of chemicals for use. The advantages of such a practice include savings of transportation costs; dependability of supply; elimination of storage space; and elimination of hazards in shipping and handling of chemicals. The present study uses an electrolytic cell with a sacrificing aluminum electrode in generating chemicals for laundry waste treatment. A bench-scale continuous flow system was built, as shown in Figure 1. Nine portions of laundry waste and one portion of seawater were introduced into a reservoir of 30-liter capacity. The mixture was pumped to an electrolytic cell of 29 cm by 6 cm by 5 cm high inside dimensions. A 1 /4-in.-thick aluminum plate served as the anode and twelve graphite rods of 1 /4-in. diameter served as the cathode. When DC power was turned on, electrons flowed to the metal anode. They readily combined with the hydrogen ions dissociated from water molecules to form hydrogen gas and escaped as rising bubbles. The remaining hydroxy ions combined with the aluminum ions to form coagulants in the cell. Large amounts of Mg(OH), flocs could also be produced.'pZ~J Oxygen and ozone were also qenerated. Chloride ions were oxidized to chlorine gas; the electrons that were formed went through the gra-